Cosmological consequences of a principle of finite amplitudes

Jonas, Caroline; Lehners, Jean-Luc; Quintin, Jerome

doi:10.1103/physrevd.103.103525

Cited by 27 publications

(32 citation statements)

References 126 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…15 Note that the case where w = −(1 + λ/2)/d corresponds to saturating the SEC, and from (A.7), it corresponds to Minkowski space in the Einstein frame. This is the basis of the loitering solution studied in [48,49,78]. 16 The only exception is when λ = −2, in which case it can be shown [47] that the solution H = H0 anḋ Φ = −βH0 is stable for any constant β > 0.…”

Section: Jhep07(2021)149mentioning

confidence: 96%

Cosmology at the top of the α′ tower

Quintin

Bernardo

Franzmann

2021

J. High Energ. Phys.

Self Cite

View full text Add to dashboard Cite

The cosmology of the fully α′-corrected duality-invariant action for the Neveu-Schwarz sector of string theory is revisited, with special emphasis on its coupling to matter sources. The role of the duality covariant pressure and dilatonic charge of the matter sector is explored in various contexts, from the low-curvature regime to non-perturbative solutions in α′. We comment on how an infinite tower of α′ corrections allows for fixed-dilaton de Sitter solutions, even in vacuum. We further investigate the necessary conditions for accelerated expansion in the Einstein frame, as well as for non-singular bounces that could resolve the big bang singularity. In particular, explicit examples are constructed, which show that the tower of α′ corrections may support an Einstein-frame non-singular cosmological bouncing background, even when the matter sector respects the null energy condition.

show abstract

Section: Jhep07(2021)149mentioning

confidence: 96%

Cosmology at the top of the α′ tower

Quintin

Bernardo

Franzmann

2021

J. High Energ. Phys.

Self Cite

View full text Add to dashboard Cite

show abstract

“…where N, N i , (3) g ij denote respectively the lapse function, shift vector, and 3dimensional induced metric on the leaves. The theory is constructed from the following quantities:…”

Section: Horava-lifshitz Gravitymentioning

confidence: 99%

“…where (3) R ij is the 3-dimensional Ricci curvature tensor, (3) ∇ i is the covariant derivative constructed from the 3-dimensional metric (3) g ij , and a i := N,i N . Extrinsic curvature K ij is the only object, invariant under general spatial diffeomorphisms containing exactly one time derivative of the metric tensor (3) g ij :…”

Section: Horava-lifshitz Gravitymentioning

confidence: 99%

“…where (3) g denotes the determinant of the 3-dimensional metric and ζ 2 = 1/16πG. It may be expressed as the difference of the kinetic and potential part 2 .…”

Section: Horava-lifshitz Gravitymentioning

confidence: 99%

“…Hence for the actions neighbouring the infinite one the variation is significant and the neighbouring ones do cancel each other, see 1 . This notion has recently received significant attention in the literature, see [2][3][4] for the cosmological considerations and 1,4 for the black hole ones. Since it is expected that the quantum gravity should resolve the black-hole singularity problem, one may ask which of the microscopic actions remain finite for non-singular black holes and conversely interfere destructively for the singular ones.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Finite Action Principle and wormholes

Chojnacki¹,

Kwapisz²

2021

Preprint

View full text Add to dashboard Cite

show abstract

Uses of complex metrics in cosmology

Jonas

Lehners

Quintin

2022

J. High Energ. Phys.

View full text Add to dashboard Cite

Complex metrics are a double-edged sword: they allow one to replace singular spacetimes, such as those containing a big bang, with regular metrics, yet they can also describe unphysical solutions in which quantum transitions may be more probable than ordinary classical evolution. In the cosmological context, we investigate a criterion proposed by Witten (based on works of Kontsevich & Segal and of Louko & Sorkin) to decide whether a complex metric is allowable or not. Because of the freedom to deform complex metrics using Cauchy’s theorem, deciding whether a metric is allowable in general requires solving a complicated optimisation problem. We describe a method that allows one to quickly determine the allowability of minisuperspace metrics. This enables us to study the off-shell structure of minisuperspace path integrals, which we investigate for various boundary conditions. Classical transitions always reside on the boundary of the domain of allowable metrics, and care must be taken in defining appropriate integration contours for the corresponding gravitational path integral. Perhaps more surprisingly, we find that proposed quantum (‘tunnelling’) transitions from a contracting to an expanding universe violate the allowability criterion and may thus be unphysical. No-boundary solutions, by contrast, are found to be allowable, and moreover we demonstrate that with an initial momentum condition an integration contour over allowable metrics may be explicitly described in arbitrary spacetime dimensions.

show abstract

Cosmological consequences of a principle of finite amplitudes

Cited by 27 publications

References 126 publications

Cosmology at the top of the α′ tower

Cosmology at the top of the α′ tower

Finite Action Principle and wormholes

Uses of complex metrics in cosmology

Contact Info

Product

Resources

About